花椰菜幼苗叶片抗氧化酶系统与抗黑腐病关系的研究

 在盆栽条件下,花椰菜抗病品种雪峰和感病品种2003X-106的幼苗在接种黑腐病菌后,叶片组织内O₂^·产生速率,SOD、POD、PAL活性,MDA含量和膜透性都有不同程度的提高和增加。与2003X-106相比,雪峰的O₂^·产生速率和SOD、PAL活性的增加更为显著,POD活性也要高于2003X-106;而MDA含量和电导率的增幅要明显低于2003X-106。表明抗病品种雪峰比感病品种2003X-106具有更强的抗黑腐病能力和抗氧化能力。     

Examination of resistance to clubroot in accessions of Brassica oleracea using a glasshouse seedling test

A glasshouse test was elaborated for assessing large numbers of seedlings ofBrassica oleracea for resistance to clubroot, a disease caused by the fungusPlasmodiophora brassicae. The method offers good control of inoculum density per plant, and requires 6–7 weeks from sowing. The results from the glasshouse test correlated well with field test results. With this method, 71 accessions ofB. oleracea reported to carry resistance to clubroot, and one susceptible control cultivar were tested with a Dutch clubroot isolate. High levels of resistance were found in several accessions of cabbage, broccoli and curly kale. F₁-populations of resistant cabbage or curly kale × susceptible cabbage were fully susceptible, indicating recessive inheritance of resistance in all cases.     

山东省白菜黑腐病苗期抗病性鉴定方法

白菜黑腐病由野油菜黄单胞杆菌Xanthomonas campestris引起，是一种世界性十字花科蔬菜重要病害。特别是近年来，黑腐病在白菜上的危害日益严重，在全国范围内均有不同程度的发生。现代生物技术的进步，给作物抗病育种带来了光明的前景，但是选育和利用抗病品种，则是一种更为经济、有效、安全的方法。在抗病育种过程中，     

Enhancement of resistance to soft rot (Pectobacterium carotovorum subsp. carotovorum) in transgenic Brassica rapa

Brassica rapa (chinese cabbage) is one of the main vegetable crops grown in Asian countries. Pectobacterium carotovorum subsp. carotovorum causes severe economic loss in this crop as well as in other Brassica crops through soft rot disease. Cysteine proteases like bromelain, papain or ficin show toxic effects to herbivorous insects and pathogenic bacteria. They have been known to be critical factors in plant defence mechanisms. The current study investigated the effect of bromelain gene (BL1) of pineapple (Ananas comosus L. Merrill) on enhancing resistance to soft rot in transgenic Brassica rapa ‘Seoulbaechu’. Three homozygous T₂ lines were inoculated with Pectobacterium carotovorum subsp. carotovorum and BL8-2 line showed the lowest rate of infected leaves (RIL) in both wound inoculation and non-wound inoculation, when the non-infected line showed 100 % RIL in both cases. The highest expression of BL1 gene was also observed in BL8-2 homozygous line. Thus, the over-expressed BL1 gene conferred enhanced resistance to soft rot in Brassica rapa.     

Race-specific aspects of polygenic resistance of barley to leaf rust,Puccinia hordei

Partial resistance of barley to leaf rust,Puccinia hordei, is characterized by a reduced rate of epidemic development in spite of a susceptible infection type. Barley cultivars vary greatly for partial resistance and its components. In a test for interaction between host cultivars and pathogen isolates most variation was of a horizontal nature. However, in the combination between Julia and the rust isolate 18, a differential interaction (vertical effect) occured; Julia had lost a small part of its partial resistance. The same interaction was found for latent period (LP), the most important component of partial resistance. Julia showed a shortened LP for isolate 18. Genetic analyses revealed, that Julia carries a polygene for longer LP not present in the other cultivars. The effect of this polygene appears to be broken by isolate 18 indicative for a gene-for-isolate relation, and even for a gene-forgene relation.Samenvatting Partiële resistantie van gerst voor dwergroest,Puccinia hordei, is gekenmerkt door een vertraagde epidemie-opbouw ondanks een vatbaar infectietype. Gerstrassen variëren sterk in partiële resistentie en haar componenten. In een toets ter bestudering van de interactie tussen waardplant en pathogeenisolaat bleek de meeste variatie horizontaal van aard te zijn. In de combinatie van Julia met isolaat 18 werd echter een differentiële interactie waargenomen; Julia had een klein deel van zijn partiële resistentie verloren. Dezelfde interactie werd waargenomen voor de belangrijkste component van partiële resistentie, de latentieperiode (LP); Julia had een iets verkorte LP voor isolaat 18. Genetische analyses toonden aan, dat Julia een polygen voor langere LP bevat; dit gen is niet aanwezig in de andere bestudeerde rassen. Er wordt verondersteld dat het effect van dit polygen door isolaat 18 is doorbroken. Dit wijst op een gen-om-isolaat en zelfs op een gen-om-gen-relatie.     

Genetics of resistance to downy mildew in Brassica oleracea and breeding towards durable disease control for UK vegetable production

Downy mildew resistance was previously identified from screening a Brassica oleracea collection against two standard UK isolates of Hyaloperonospora parasitica. Sources of resistance were chosen from this material and developed further in this study by generating doubled haploid (DH) and inbred lines. Seedlings from the new lines were tested for resistance to a larger collection of H. parasitica isolates collected in 2001–2002 and 2007–2008 from the main broccoli and cauliflower production regions of the UK. Three lines (derived from borecole or summer cabbage) were broadly resistant to the pathogen isolates. Three of the remaining lines exhibited strong isolate‐specific resistance; several examples of weak or basal level of resistance to some isolates were observed. A new H. parasitica variant collected in 2008 was virulent in the broadly resistant lines, but was avirulent in a line with narrow specificity of resistance. The F₂ and BC₁ seedlings derived from outcrossing each of the three broadly resistant lines to susceptible broccoli and cauliflower lines segregated in a manner indicating that the resistance was controlled by a single dominant gene. No susceptibility was observed amongst F₂ seedlings derived from intercrossing the three resistant lines, indicating that they all share the same or closely linked broad‐spectrum resistance gene(s). DH lines were produced from F₁ plants, and resistant plants were further backcrossed to produce broccoli and cauliflower‐like lines that could be useful pre‐breeding material. A combination of resistance from lines with broad and narrow specificity is recommended for controlling downy mildew in UK brassica production.     

香蕉黑腐病菌(Botryodiplodia theobromae)的PCR检测

 根据香蕉黑腐病菌可可球二孢菌(Botryodiplodia theobromae)与其它香蕉病原真菌核糖体基因转录间隔区(rDNA-ITS)ITS1和ITS2间序列差异,设计了特异引物Bth-S(5'-TCTCCCACCCTTTGTGAAC-3')和Bth-A(5'-AAAAGT-TCAGAAGGTTCGTC-3'),利用此引物对包括可可球二孢菌在内的21个菌株基因组DNA进行PCR扩增,结果只有4个可可球二孢菌菌株扩增到422bp特异带,其它17个菌株无扩增产物。灵敏度测试结果表明此特异引物能对1pg的可可球二孢菌基因组DNA进行扩增。对自然感染黑腐病的香蕉果实组织和接种可可球二孢菌或多种香蕉病原真菌混合接种的果实组织进行检测,Bth-S和Bth-A引物对不仅能够在自然感染黑腐病果实组织中特异检测到可可球二孢菌,而且能在未显症和发病的接菌香蕉果实组织中特异检测得到可可球二孢菌。这为香蕉可可球二孢菌潜伏侵染检测提供了技术支持。     

Durability of resistance in lily to basal rot: evaluation of virulence and aggressiveness among isolates ofFusarium oxysporum f. sp.lilii

Prospects of durability of resistance in lily to basal rot have been evaluated by testing the virulence and aggressiveness of 31 isolates ofFusarium oxysporum f. sp.lilii towards a number of different resistance sources inLilium spp. Isolates differed strongly in aggressiveness as did species and cultivars ofLilium spp. in resistance. Significant interactions were observed between isolates of the pathogen and genotypes ofLilium spp., but the magnitude was very small compared to the main effects. The interactions were mainly due to a small group of isolates with low aggressiveness. It is argued that the interactions might be based on minor genes. No major break down of the resistance was found. For practical purposes it will be sufficient to use highly aggressive isolates in screening tests.     

Genotype-isolate interaction for resistance to black stem in sunflower (Helianthus annuus)

Two experiments were undertaken to determine the partial resistance of sunflower genotypes to seven isolates of Phoma macdonaldii . In the first experiment, 28 genotypes, including recombinant inbred lines and their parents, M6 mutant lines developed by gamma irradiation, and some genotypes from different geographical origins, were used. The experiment consisted of a split-plot design with three replications, each with 12 seedlings per genotype per isolate, in controlled conditions. Seven days after inoculation, plantlets were scored on a 1–9 scale for percentage necrotic area. Highly significant differences were observed among genotypes, isolates and their interactions. The presence of a differential interaction between genotypes and P. macdonaldii isolates was confirmed in a second experiment using 12 genotypes representing large variability for partial resistance to P. macdonaldii isolates, as identified in the first experiment. Inbred lines B454/03, ENSAT-B5 and LC1064C were the most susceptible sunflower genotypes, whereas two American lines SDR19 and SDR18 presented high partial resistance to all P. macdonaldii isolates studied. The least and most aggressive isolates were MA6 and MP3, respectively. Isolates interacted differentially with sunflower genotypes. This study identified two genotypes (AS613 and PAC2) presenting specific resistance to isolate MP8. The results also showed a wide range of isolate-nonspecific partial resistances among the lines tested. The information presented here could assist sunflower breeders to choose parents of crosses for breeding of durable resistance to phoma black stem disease.     

Characterization,genetic diversity and distribution of Xanthomonas campestris pv. campestris races causing black rot disease in cruciferous crops of India

Black rot, caused by Xanthomonas campestris pv. campestris (Xcc) is a disease of crucifer crops. The objective of this study was to characterize races of Xcc, their distribution and genetic diversity in India. Two hundred and seventeen isolates of bacteria were obtained from 12 different black rot‐infected crucifer crops from 19 states of India; these were identified as Xcc based on morphology, hrpF gene and 16S rRNA gene based molecular markers and pathogenicity tests. Characterization of races was performed by using a set of seven differential crucifer hosts, comprising two cultivars of turnip (Brassica rapa var. rapa) and cultivars of Indian mustard (B. juncea), Ethiopian mustard (B. carinata), rapeseed mustard (B. napus), cauliflower (B. oleracea) and Savoy cabbage (B. oleracea var. sabauda). Races 1, 4 and 6 of Xcc were identified and, among these races, race 1 followed by race 4 dominated most of the states of India. Genetic diversity of the Indian isolates of Xcc was analysed using repetitive sequence‐based PCR (rep‐PCR) including primers for REP (repetitive extragenic palindromic), ERIC (enterobacterial repetitive intergenic consensus) and BOX (amplifying with BOX A1 R primer) repetitive elements. This method of fingerprinting grouped the isolates into 56 different DNA types (clusters) with a 75% similarity coefficient. Among these clusters, DNA types 22 and 53 contained two different races 1 and 4, whereas DNA type 12 contained races 1, 4 and 6. However, no clear relationship was observed between fingerprints and races, hosts or geographical origin.     

Response of black rot in cabbage to spatial distribution of inoculum

Disease progress of black rot in cabbage crop was studied over three years in field plots to compare the effects of uni-focal and multi-focal inoculum applied in equal amounts per plot. Disease progress (plant incidence and leaf incidence) was plotted over time, three dimensional maps were made, and disease aggregation was studied by means of geostatistics, black-black counts and Moran's I statistic. Black rot progress was primarily due to focus expansion. Secondary foci may appear at short distances from the initial focus but they usually merge with the expanding initial focus. Anisotropy occurred occasionally but was of minor importance. Disease proceeds faster in plots with multi-focal inoculation than in those with uni-focal inoculation. Probably, serious epidemics in Dutch cabbage fields originate from large numbers of foci.     

烟草根黑腐病菌致病力分化及品种抗性差异研究

 烟草根黑腐病由根串珠霉（Thielaviopsis basicola (Berk.et Br.)Ferr.）引起,主要为害烟株的根部,可使根部组织呈特异性黑色坏死而导致烟苗死亡或地上部分生长不良。该病是世界性的烟草病害,在各产烟国家如美国、日本、加拿大等国普遍发生,在我国主要分布于河南、山东、安徽、云南等地     

The susceptibility of Brassica oleracea cultivars to Plasmodiophora brassicae (clubroot)

An evaluation of 404 Brassica oleracea cultivars for susceptibility to Plasmodiophora brassicae (clubroot) at one field site in northern Scotland over the four years 1979-82 is reported. The population of P. brassicae at this site possessed a high degree of virulence to B. oleracea as determined by seedling tests in a glasshouse environment, using the European Clubroot Differential series. No statistically significant differences in susceptibility were consistently identified between cultivars when tested under field conditions. Data over years and over crops were analysed by the residual maximum likelihood technique. Differences between cultivars were small compared with cultivar x year interactions. No obvious differences were identified in susceptibility between the crop types Brussels sprout, cabbage, calabrese and cauliflower. Disease levels as analysed over all field trials increased markedly in years three and four of this experiment compared with the first two years.     

冠菌素诱导甘蓝幼苗抗黑腐病及其机理初步研究

以甘蓝 Brassica oleracea L.感病品种"庆丰"为材料,通过叶面喷施冠菌素(coronatine,COR)和人工接种黑腐病菌——野油菜黄单胞菌野油菜致病变种(Xanthomonas campestris pv.campestris)的方法,研究了COR诱导甘蓝幼苗抗黑腐病的效果及其生理生化机制。结果表明, COR在质量浓度为0.01、0.1和1.0 mg/L下均具有诱导甘蓝幼苗抗黑腐病的效果,其中1.0 mg/L 处理的病情指数为38.2,诱抗率为43.7%,诱导抗病效果最好。与对照相比,随着COR质量浓度的提高,叶片中过氧化氢酶(CAT)活性和超氧阴离子(O2-)产生的速率明显增加,而过氧化物酶(POD)的活性增加不明显,超氧化物歧化酶(SOD)活性和丙二醛(MDA)的含量明显下降。表明COR具有诱导甘蓝幼苗抗黑腐病的作用,而这种作用可能与COR能调控甘蓝幼苗中抗氧化酶活性、提高O2-产生速率以及降低MDA的含量相关。     

Quantifying resistance to Plasmodiophora brassicae in Brassica hosts

Plasmodiophora brassicae causes clubroot of crucifers. A quantitative PCR (qPCR)‐based protocol was developed to measure P. brassicae DNA in the roots of susceptible, intermediately susceptible, intermediately resistant and resistant Brassica hosts, and the non‐host wheat, at 5, 10, 15, 20 and 42 days post‐inoculation (dpi). The final reaction of each plant genotype was recorded as an index of disease at 42 dpi. Plasmodiophora brassicae DNA showed an increase in susceptible and moderately resistant hosts from 5 to 42 dpi, in contrast to a decrease in a highly resistant host and the non‐host wheat over the same period. Index of disease was significantly positively correlated with the amount of P. brassicae DNA in the roots at 5, 15, 20 and 42 dpi in one experiment, and at 10, 15, 20 and 42 dpi in a repeated experiment. Significant positive correlations also existed between the amounts of P. brassicae DNA in the roots at 42 dpi and those at 5, 10, 15 and 20 dpi in one experiment, and those at 10, 15 and 20 dpi in a repeated experiment. The results generated by the qPCR assay were validated by microscopic examination of roots inoculated with P. brassicae. The qPCR‐based protocol developed in this study allows for the accurate quantification of P. brassicae DNA in host root tissues as early as 5 dpi, and may serve as a useful tool to evaluate pathogen proliferation and development in the roots.     

Breakdown of Pl2, a major gene of resistance to apple powdery mildew, in a French experimental orchard

Pl2 , a major resistance gene to powdery mildew originating from Malus zumi , is mainly used in apple-breeding programmes. In an experimental orchard in France, an increase of susceptibility to powdery mildew was observed on apple genotypes carrying Pl2 . This increase of susceptibility could not be explained by an effect of the age of the trees, or by an effect of the amount of inoculum on expression of the resistance Pl2 . It was demonstrated by tests of pathogenicity in controlled conditions that isolates of Podosphaera leucotricha sampled in this orchard were virulent to Pl2 . The appearance of virulent isolates within 6 years after planting apple genotypes selected for the presence of Pl2 resulted in a breakdown of the resistance. Ten years after planting, the percentage of genotypes that were still resistant to powdery mildew varied between 2 and 56%, depending on the progenies. This suggested that additional quantitative resistance genes may influence the durability of the resistance Pl2 .     

甘蓝类蔬菜品种(系)苗期根肿病抗性鉴定

芸薹根肿菌侵染引起的根肿病是影响甘蓝类蔬菜产量和品质的主要病害之一,抗病品种的培育是防治根肿病最经济有效的方法。本研究以根肿菌4号生理小种为菌源,对花椰菜、结球甘蓝、青花菜、芥蓝和苤蓝6个甘蓝变种共306份品种(系)进行苗期根肿病抗性鉴定,结果显示,甘蓝类抗根肿病材料缺乏,仅在青花菜中发现1份高抗(HR)材料,感病(S)和高感(HS)材料比例占65%以上,中抗(MR)材料在松花菜和结球甘蓝中所占比例均在30%以上。对抗病比例和平均病情指数2个指标的联合评价结果显示,结球甘蓝整体抗性水平高于其他变种,芥蓝和苤蓝抗性最差。另外,对结球甘蓝‘先甘336’(R)×甘蓝/青花菜杂交后代及花椰菜‘托尼’(MR)×青花菜的杂交后代进行苗期根肿病抗性鉴定,结果表明,杂交后代相对于父本病情指数都有所降低,抗性相对提高,且父本病情指数越低,后代表现较高抗性的概率越大。鉴于此,在今后抗病组合的选择与选配过程中,父本和母本最好都具有较高的抗性。本研究将为甘蓝类蔬菜抗根肿病品种培育提供材料支撑和技术参考。     

糯高粱种质资源对川南高粱丝黑穗病的抗性鉴定

为明确新选育和引进的糯高粱种质资源对川南高粱丝黑穗病菌主要生理小种的抗性,利用4个高粱鉴别寄主分别对2013年和2014年自川南泸州、宜宾、自贡3市高粱上采集的丝黑穗病菌Sporisorium reilianum进行生理小种鉴定,并于2014—2018年对新选育和引进的55份不育系、88份恢复系和20份常规品种糯高粱种植资源进行丝黑穗病抗性鉴定。结果表明,川南3市采集的高粱丝黑穗病菌生理小种均为1号生理小种。不育系糯高粱种植资源对丝黑穗病菌1号生理小种抗性较强,对丝黑穗病免疫材料有45份,87.3%不育系糯高粱种植资源为抗性材料。恢复系糯高粱种质资源抗丝黑穗病菌1号小种的能力弱于不育系,对丝黑穗病表现为免疫、高抗、抗病、中抗的种质资源分别为32、1、2和5份,抗病恢复系糯高粱种质资源占恢复系糯高粱种质资源总数的45.5%。糯高粱种质资源常规品种对丝黑穗病菌1号小种的抗性最差,抗病糯高粱种质资源常规品种占常规品种总数的45.0%,其中对丝黑穗病免疫的糯高粱种质资源常规品种仅有1份,为国窖红3号;对丝黑穗病高抗和抗病的糯高粱种质资源常规品种无,主要表现为中抗,应加强川南地区糯高粱常规品种的...